JP2019508639A - Proportional valve - Google Patents

Abstract

  The invention relates to a proportional valve (1), wherein the valve (1) comprises an energizing element (2), a pressure air connection (5) for pressure air supply connection, an operation connection (4) and an exhaust connection ( 3) will be equipped. The valve (1) is connected in series with one another and is axially actuated by three axially movable valve bodies (7, 8, 9), ie a first valve biased by a biasing element (2) A body (7), a second valve body (8) biased by the first valve body (7), and a third valve body biased by the second valve body (8) 9). In the basic state of the proportional valve (1), the first valve body (7) is separated from the second valve body (8) and the second valve body (8) is separated from the third valve body (9). First seal sheet (25), third valve body (9) and housing (15) acting between the first valve body (7) and the second valve body (8) in the valve (1) Form and arrange the second seal sheet (26) acting between them in the following manner, ie, when the first valve body (7) is displaced, the biasing element (2) and it cascaded Or venting the working connection (4) by changing the axial positioning of the first, second and third valve bodies (7, 8, 9) acting on the valve or the working connection (4) Different switching states can be set to hold the pressure present above.

Description

  The invention relates in particular to a proportional valve for biasing a pneumatic actuator, wherein the valve comprises a biasing element, a pressure air connection for the pressure air supply connection, an operating connection and an exhaust connection.

Valves of this kind are known from the prior art in various ways. As a proportional valve, it must be suitable to supply as adjustable as possible an (air) pressure to the operating connection provided for the connection of the pneumatic valve as accurately as possible. The biasing element is therefore used to move the valve normally to different valve positions by appropriately biasing the valve, thereby selectively coupling the operative connection to the pressure supply or exhaust, or ( Disconnect from both to maintain the pressure present at the working connection. As a proportional valve, it is also necessary to allow an intermediate position between the complete intake and the complete exhaust of the valve connected to the operating connection.
For the sake of clarity, any pressure activatable actuator can be understood in the present application as a pneumatic actuator, in particular as a pneumatic drive.

  Proportional valves of the type described above are relatively expensive in terms of their construction and operation.

  In the prior art, so-called slide valves are often used, according to which at least one linear slidable valve body is arranged laterally of the valve body depending on its position and an opening which influences the air flow Open or close (fully or partially). However, unlike in the case of the valve seat, it is always necessary to take into account the leaks which become a problem in precise use situations due to the lack of a sealing sheet which effectively blocks the flow, which is possible within the scope of the invention It should be reduced as much as possible or completely prevented.

  Furthermore, from DE 10 2012 0177 13 A1 a proportional valve of the same kind is already known in the form of a positioner in which the power stage (which is actuated by the former acting as a biasing element) is A spring-loaded two poppet valves are provided as pressure-to-path transducers, to which pressure is applied from a common control space and to increase the pressure present in the control space in order to realize different switching states It is continuously energized by Due to the poppet valves to be arranged on different sides of the common control space, the positioner disclosed in DE 10 2012 0177 13 A1 has a structural volume which can never be small and the invention To make it smaller.

  U.S. Pat. No. 2,850,330 discloses a valve group for use in a brake system of a tractor with an articulated vehicle, whereby it is connected in series with one another to form two valves. A total of three axially movable and cascadable adjustable valve bodies are provided. The first valve can then be used to selectively exhaust the first working connection of the brake system of the articulated vehicle or to be coupled with the tractor-side pressure air connection, while the second valve The second emergency operation connection of the brake system of the articulated vehicle can be selectively vented or coupled to a second emergency pressure air connection on the tractor side. A transition from the first switching state in which the corresponding operating connection is exhausted by a change in the position of the first valve body to a second switching state in which the corresponding operating connection is coupled with the tractor-side pressure air connection .

  From the above background it is an object of the present invention to improve the kind mentioned at the outset, which in particular requires only the smallest possible (lateral) construction volume and at the same time can operate safely and accurately in a very simple manner Providing a proportional valve.

  The problem is solved by the proportional valve according to claim 1. Preferred configurations of such a valve are revealed by the dependent claims and the detailed description which follows.

In addition to the features mentioned at the outset in the valve according to the invention, the first valve which is connected in series with one another and which is axially actuable by three valve bodies, ie-by means of a biasing element. Body,
-A second valve body biased by said first valve body,
The valve comprises a third valve body biased by said second valve body,

  In this case, in the basic state of the proportional valve, the first valve body is separated from the second valve body and the second valve body is separated from the third valve body, and the first valve body and the second valve in the valve The first seal sheet acting between the bodies and the second seal sheet acting between the third valve body and the housing were formed and arranged in the following manner, that is, the first valve body was displaced Evacuating the active connection through coupling with the exhaust connection by changing the axial positioning of the biasing element and the first, second and third valve bodies which it acts in cascade. Differently for supplying air to the working connection through coupling with the pressure air connection or for maintaining the pressure present on the working connection through blocking of the working connection from both the exhaust connection and the pressure air connection And can be set to set the To location.

  Thus, unlike the prior art described above, according to the invention, the two poppet valves which are components of the pressure-path converter are not energized by the pressure in the common control space, but rather in the valves. A cascaded adjustment of the valve bodies which influences the fluid flow is carried out, wherein the first valve body is biased by the biasing element and each valve body connected back to the first valve body Are energized continuously (especially purely mechanically) by means of the respective predeter- mined valve body. In order to make the biasing direction axial for all three valve bodies, the structural volume required for the valve according to the invention can be extremely miniaturized (especially in a direction transverse to the operating direction of the valve bodies) It is clear.

  In addition, very little or no leakage operation can be ensured due to the fact that two sealing sheets can be provided inside the valve, each of which is associated with at least one valve body, Is a great advantage, in particular in maintaining the pressure present at the operating connection, while minimizing the pressure energy consumption of the valve. Furthermore, the valve according to the invention can operate proportionally with very high control properties. Because of the cascade-like displaceability of the valve according to the invention, an (optional) intermediate position can be set effectively between "full air supply" and "full exhaust", whereby in particular a pressure valve or drive It is possible to achieve high positional accuracy when controlling the

  In a preferred embodiment of the invention, the biasing element acting on the first valve body to bias the first valve body of the valve according to the invention is hydraulic, pneumatic or electromechanical in principle Can be operated by

  However, in particular in order to achieve the lowest possible (electrical and barometric) energy consumption overall, the actuating element is formed as a pneumatic pilot valve which cooperates with the first valve body via the control pressure space. Is preferred. In that case it is advantageous as a very energy-saving configuration that the pilot valve comprises a piezo-electric flex actuator, as disclosed for example in EP-A-0 949 812 A1 in which the preferred pilot valve is described. is there.

  The valve according to the invention can thus be regarded as a pneumatic pressure positioner with an output stage (in particular comprising three valve bodies), wherein it is biased by means of a pilot valve which acts as a biasing element on the first valve body. Do. It is highly preferred that the pilot valve be configured as a (proportional) 3 / 2-way valve.

  In a further preferred embodiment of the invention, the first valve body of the valve according to the invention is formed by a thin-film plate provided with a thin-film plate shaft axially extending and having an axial hollow portion, The membrane plate is preloaded by means of a spring in the direction of the control pressure space and interlocked with the first membrane in order to adjust the axial position, and is preset in the control pressure space on one side of the membrane. Control pressure (controlled by the pilot valve) is applied.

  Thus, the control pressure acts on the first membrane on the control pressure space side so that the first membrane deforms according to the differential pressure set on both sides of it, and thereby (with the first membrane via the membrane plate) Biasing, i.e. axial sliding, of the coupled first) valve body in the direction of the second valve body is performed.

  According to another preferred additional configuration of the invention, the second valve body is formed by a valve plunger which is preloaded in the direction towards the first valve body by means of a spring, which valve plunger is said first valve. Depending on the axial position of the body, it is separated or joined from the membrane plate shaft, whereby a first sealing sheet is formed in the contact surface between the membrane plate shaft and the valve plunger. It is then preferable to form a sealing surface either on the side of the (free) end of the membrane plate shaft pointing in the direction of the valve plunger or on the end of the valve plunger pointing in the direction of the membrane plate shaft. The sealing surface forms a sealing sheet with the corresponding sealing edge of the valve plunger or membrane plate shaft.

  Within the framework of the present invention, the third valve body can be effectively formed by a socket element, which is preloaded against the second sealing sheet by the spring in the direction towards the valve plunger The valve plunger, which is joined on the socket element, can be lifted from the second seal seat by sliding axially.

  Overall, therefore, the cascaded adjustability of the valve according to the invention is achieved, in particular in the basic position set in particular when the control pressure space is evacuated (the membrane plate and shaft) Is spaced apart from the second valve body (valve plunger) and the second valve body (valve plunger) from the third valve body (socket element). Thus, during operation of the valve according to the invention, the biasing element first causes the first valve body (membrane plate and shaft) to interact with the second valve body in the region of the contact surface forming the first sealing sheet. It slides against the spring preload in the direction of the second valve body (valve plunger) until it contacts. Subsequently, the first valve body is further slid by the biasing element so that the first and second valve bodies are joined until the second valve body (valve plunger) is joined to the third valve body (socket element). Sliding together in the direction of the third valve body and then lifting the third valve body, which is preloaded by the spring against the second seal sheet by further manipulation of the valve body, from the second seal sheet Can.

  The fluid connection of the actuating connection and the exhaust connection is then effectively maintained (starting from the basic position) until the first valve body is airtightly joined to the second valve body. The switching state which holds the pressure present on the working connection formed after that axial position is set by the distance between the second valve body and the third valve body formed in the basic position And the second valve body is joined to the third valve body and held until the third valve body lifts from the second seal sheet. The valve is then switched to supply air to the actuating connection.

  According to a preferred additional configuration of the invention, the surfaces forming and / or cooperating with the first and / or second sealing sheets are adjusted to control the rate of leakage and / or control properties. In order to improve the quality of the material, it is in particular made of a polymer material which has a different elasticity than the sealing partner as required. This makes it possible to achieve very delicate displacements, in particular with regard to the point of the intermediate position required for proportional operation of the valve.

  According to the invention, furthermore, the exhaust connection is connected to the permanently evacuated exhaust space of the valve, which exhaust space is axially hollow of the membrane plate shaft when the membrane plate shaft is not joined to the valve plunger. It is preferred that the section be fluidly coupled to the operative connection and that the membrane plate shaft be fluidly disconnected from the operative connection if the membrane plate shaft is hermetically sealed to the valve plunger.

  In addition, the exhaust space is partitioned by the first membrane and the second membrane, whereby the membrane plate shaft (with an axial hollow) penetrates the second membrane axially by its free end. It can be suitably configured. Thus, between the exhaust space and the working connection (depending on whether the axial hollow of the membrane plate shaft is open by separating it from the valve plunger or shut off by sealing it airtight to the valve plunger) Fluid flow connections can be formed or shut off.

  Furthermore, the working pressure space coupled with the working connection of the valve is partitioned by the second membrane and the second sealing sheet, wherein the working pressure space is dependent on the position of the membrane plate, the valve plunger and the socket element. It is preferred that the pressure air connection or the exhaust connection be fluidly coupled or be configured to be isolated from the pressure air connection and the exhaust connection.

  In order to preload the membrane plate and / or the socket element with a spring, it is preferred that both the membrane plate and / or the spring element which preloads the socket element be supported on the housing of the valve.

  By means of at least three spring elements which are all arranged equidistantly to the central axis of the membrane plate (as well as the membrane plate shaft) and are equiangularly offset from one another in pairs. It can be very suitably configured to preload the membrane plate. Therefore, in the case of having three spring elements, it is preferable to shift each by 120 °. Moreover, when it has four spring elements, it each shifts | deviates 90 degrees, and the same may be said of the case beyond it.

  Within the framework of the present invention, the second membrane preferably also acts to radially fix the (axially induced) membrane plate shaft. Therefore, according to another preferred additional configuration of the valve according to the invention, the membrane plate is combined with the second membrane, in particular in the region of the membrane plate shaft, wherein the second membrane is an axially derived membrane Act to radially support the plate.

  According to yet another preferred additional configuration of the invention, the valve plunger is preloaded in the direction of the membrane plate shaft by a spring supported on the socket element with respect to the spring preload of the valve plunger. Thereby, the spring element, which preloads the valve plunger to further slide all three valve bodies in case the valve plunger is already joined on the socket element, is countered to its spring pressure It has the advantage of eliminating the need for compression. Thus, the spring element preloading the valve plunger does not bear a further increase in the spring pressure to be overcome when further sliding the first, second and third valve bodies. Therefore, only a small increase in control pressure in the control pressure space is required to lift the third valve body from the second seal seat compared to what is required for bearing the valve plunger spring on the housing Therefore, the control characteristics of the valve according to the present invention can be further improved.

  According to yet another preferred form of the invention, the non-biased valve plunger is separated by a given sliding distance from the socket element joined to the second sealing sheet. Thereby, in particular the switching states set to maintain a specific pressure on the operating connection of the proportional valve according to the invention are clear from both the other switching states for air supply and exhaust of the operating connection. Can also be used to improve the control characteristics of the valve.

  Furthermore, in the frame of the invention, the spring element preloading the membrane plate, the spring element preloading the valve plunger and the spring element preloading the socket element are different and mutually coordinated spring characteristic curves. It is preferable to have it because it allows the control characteristics of the valve to be adapted very well to the required performance at each point in time. From the perspective of cascaded adjustment, the spring stiffness of the spring element preloading the socket element is higher than the spring stiffness of the spring element preloading the valve plunger, and the spring stiffness of the spring element preloading the valve plunger is It is highly preferred that the membrane plate be made higher than the spring stiffness of the prestressing spring element.

  Furthermore, according to a preferred embodiment of the invention, the valve according to the invention comprises a pressure regulator for adjusting the pressure present on the pressure input of the pilot valve, in particular on the input of said pilot valve The pressure may be diverted or introduced from a pressure air supply connected to the pressure air connection.

It is a sectional view showing one example of a valve concerning the present invention.

It is explanatory drawing which showed roughly the structure of the spring element which pre-loads a 1st valve body in the Example of FIG.

  An embodiment of the valve according to the invention will now be described in detail with reference to the accompanying drawings.

  An embodiment of a proportional valve 1 according to the invention is shown in FIG. 1 and comprises a biasing element 2 in the form of a pneumatic pilot valve 31. The structure of the pilot valve 31 will be described in detail later.

  The valve 1 further comprises a working connection 4 for connection to an exhaust connection 3 and a pressure valve (not shown) biased by the valve 1 and a pressure air supply having a given pressure, for example 8 bar. A connection 5 to the source is provided. Furthermore, a pneumatic pilot valve is provided which comprises a pressure regulator 6, whereby a pressure lower than the pressure present on the connection 5 for the pressure air supply, for example 1.2 bar, as the actuating element 2. Can be generated as an initial pressure. Since the pressure regulator is widely known in the prior art and its specific configuration is not important from the point of view of the present invention, a detailed description of its functional scheme is omitted.

  The valve 1 further comprises three valve bodies 7, 8, 9 which are connected in series to one another and can be axially displaced in accordance with the arrow R in each case.

  The first valve body 7 (topmost in FIG. 1) then comprises a membrane plate 10 as well as a membrane plate shaft 11 with an axial hollow 12.

  The membrane plate 10 is in operative connection with the first membrane 13 (in this case by mechanical connection), whereby a control pressure space 14 is formed above the first membrane 13 and the membrane plate 10. The air pressure present in the control pressure space 14 is controlled by the pilot valve 2 acting as the actuating element 2. Furthermore, the first valve body 7 (formed by the membrane plate 10 and the membrane plate shaft 11) is preloaded by the spring in the (axial) direction pointing towards the control pressure space 14. For this purpose, in the embodiment shown, a total of three spring elements 16 are mounted on the housing 15 of the valve 1, one of which in FIG. 1 is present in the cross-sectional view (left of the central axis M), the rest Both spring elements (only one of which can be seen in FIG. 1) lie in front of or behind this cross section. All three spring elements 16 are arranged equidistantly (ie equal radial distances) with respect to the central axis M and in a plane extending perpendicularly to the central axis M (about the central axis M In the direction of the control pressure space 14 of the first valve body 7 completely symmetrical with respect to the axial central axis M. Load is achieved. A symmetrical arrangement of these three spring elements 16 in total is shown in FIG.

  In the present embodiment, the second valve body 8 is formed by a valve plunger 17 or the third valve body 9 is formed by a socket element 18. The valve plunger 17 is then preloaded in the direction of the first valve body 7 (= membrane plate 10 and membrane plate shaft 11) by the spring 19 supported on the socket element 18, while the socket element 18 is mounted on the housing 15. It is preloaded by a spring 20 supported on

  In the basic position of the valve 1 shown in FIG. 1, all three valve bodies 7, 8, 9 movable in the axial direction of the valve 1 are preloaded in the same direction but spaced apart in pairs.

  The thin film plate shaft 11 is combined with the second thin film 21, and the second thin film seals and surrounds the thin film plate shaft 11 and exists between the first thin film 13 and the second thin film 21. It separates the exhaust space 22 leading to the exhaust connection 3 (constantly evacuated) from the operating pressure space 23 leading to the operating connection 4. The second membrane 21 can then simultaneously serve to radially support the membrane plate shaft. Due to the distance between the free end of the membrane plate shaft 11 formed in the basic position of the valve 1 and the valve plunger 17, the operating pressure space 23 in the valve state shown in FIG. Pressure valve) is exhausted.

  The valve plunger 17 has a polymeric material acting as a sealing surface 24 on the top surface facing the membrane plate shaft 11, on which the lower edge 25 of the membrane plate shaft 11 joins while forming the first sealing sheet Can. This flexible sealing surface enables a very accurate proportional fine adjustment, depending on the hardness of the polymer in the vicinity of the contact area when adjusting the valve.

  That is, by sliding the first valve body 7 until the lower edge 25 of the thin film plate shaft 11 is airtightly joined to the upper surface 24 of the valve plunger 17 (by appropriately increasing the pressure existing in the control pressure space 14) Then, the connection between the exhaust space 22 formed by the axial hollow portion 12 of the thin film plate shaft 11 and the operating pressure space 23 is cut off, and as a result, the exhausting of the preceding operating pressure space 23 is completed.

  In the embodiment of the proportional valve 1 according to the invention illustrated, a second sealing sheet is formed by the sealing edge 26 fixed to the housing and pointing downwards in FIG. 1 to the third sealing edge. A sealing surface 27 made of a polymeric material, in which the socket element 18 functioning as the valve body 9 is preloaded by the spring 20, with the socket element side also cooperating with the sealing edge 26 to form a second sealing sheet. Is provided. Below the second sealing sheet there is a pressure supply space 28 which is connected with the connection 5 for pressure supply, so that the pressure supply space 28 airtightly bonds the upper surface of the socket element 18 to the sealing edge 26 In some cases, it is fluidically isolated from the operating pressure space 23.

  That is, the first valve body 7 is joined to the second valve body 8 (by appropriately biasing the first valve body 7 with the pilot valve 2), and the second valve body 8 is a third valve body Only when the first valve body 7 is slid until it is joined to 9 is the third valve body 9 (= socket element 18) a second seal by the further increase of the control pressure in the control pressure space 14 It leads to lifting off of the seat so that the operating pressure space 23 is fluidically coupled with the pressure supply. From the viewpoint of biasing of the third valve body 9, it is preferable to form a hard stopper between the valve plunger 17 and the socket element 18.

  The very good control properties of the valve according to the invention are achieved in particular because of the distance between the first, second and third valve bodies 7, 8 and 9 formed in the basic state, The reason is that it allows the different fluid operating states of the valve to be very well differentiated and easily controlled.

  It is understood that the control of the valve according to the invention is (on the other hand, in spite of the cascaded configuration) very simple. For this purpose, a magnet element 29 can be provided on the first valve body 7 (for example in the area of the membrane plate edge), so that by using a suitable position sensor 30, the axial position of the first valve body 7 Can be accurately determined.

  Due to the purely mechanical connection of the three valve bodies 7, 8, 9 and also for the displacement path between the different valve states, which are fixedly given by the position of the sealing sheet, (only) by means of the position sensor 30 Control of the valve can be performed using the (axial) position of the first valve body 7 that is detectable.

  Further shown in FIG. 1 is a pneumatic pilot valve 31 used as a biasing element 2. In this embodiment, it is formed as a proportional 3 / 2-way valve.

  A pressure input 33 is provided, which in the present example is supplied with the air pressure provided by the pressure regulator 6. In addition, a pilot valve exhaust connection 32 (possibly coupled with the exhaust connection 3 of the valve 1) is provided, and a pilot valve operating output 34 fluidly coupled to the control pressure space 14 of the valve 1 is provided. Pilot valve actuation output 34 is selectively vented (i.e., fluidically actuated) using a piezoelectric flex actuator 35 that is electrically energizable and thereby pivotable in the direction of arrow B in the area of the free end. Can be coupled to the pilot valve exhaust connection 32) or partially or completely coupled to the pressure present on the pressure input 33 of the pilot valve 31. The pilot valve 31 is thus for the first valve body 7 of the valve 1 according to the invention while controlling the pressure present in the control pressure space 14 as described above with very high control quality and low energy consumption. It can act as a biasing element.

Claims (18)

In particular a proportional valve for energizing a pneumatic actuator, wherein the valve (1) is a biasing element (2) and a pressure air connection (5) for pressure air supply connection and an operating connection (4) And a proportional valve (1) comprising an exhaust connection (3),
Three valve bodies (7, 8, 9) which are connected in series and which are all axially movable, ie-a first valve body (7) which is biased by a biasing element (2) ,
-A second valve body (8) biased by said first valve body (7);
The valve (1) comprises a third valve body (9) biased by said second valve body (8);
In the basic state of the proportional valve (1), the first valve body (7) is separated from the second valve body (8) and the second valve body (8) is separated from the third valve body (9). And the first seal sheet (25) and the third valve body (9) that act between the first valve body (7) and the second valve body (8) in the valve (1) and the housing ( 15) form and arrange the second seal sheet (26) acting between them in the following manner;
That is, when the first valve body (7) is displaced, the axial direction of the biasing element (2) and the first, second and third valve bodies (7, 8, 9) which act in cascade Whether to evacuate the working connection (4) through coupling with the exhaust connection (3) by changing the position setting or to supply air to the working connection (4) through coupling with the pressure air connection (5) Or different switching states for maintaining the pressure present on the working connection (4) through the disconnection of the working connection (4) from both the exhaust connection (3) and the pressure air connection (5) Proportional valve configured and arranged to be configurable.   2. Proportional valve according to claim 1, characterized in that the biasing element (2) operates according to hydraulic, pneumatic or electromechanical principles.   Biasing element (2) as a pneumatic pilot valve (31) which cooperates with the first valve body (7) via the control pressure space (14) and preferably comprises a piezoelectric bending actuator (35) The proportional valve according to claim 1, wherein the proportional valve is formed.   A first valve body (7) is formed by a thin film plate (10) provided with a thin film plate shaft (11) extending axially and having an axial hollow portion (12), wherein said thin film The plate (10) is spring-loaded in the direction of the control pressure space (14) and interlocked with the first membrane (13) to adjust the axial position, the control pressure space being on one side of the membrane The proportional valve according to claim 3, wherein a control pressure preset in (14) is applied.   A second valve body (8) is formed by a valve plunger (17) preloaded in the direction towards the first valve body (7) by a spring, said valve plunger being said first valve body (7) Are separated or joined to the membrane plate shaft (11) according to the axial position of the first sealing sheet (25) in the contact surface between the membrane plate shaft (11) and the valve plunger (17) 5. A proportional valve according to claim 4, characterized in that it is formed.   The third valve body (9) is formed by the socket element (18), which is preloaded against the second sealing sheet (26) by the spring in the direction towards the valve plunger (17) Proportional valve according to claim 4 or 5, characterized in that it can be lifted from said second sealing sheet (26) by axially sliding a valve plunger (17) joined on a socket element (18). .   Polymer to form a first and / or a second sealing sheet and / or to cooperate with them (24, 27) to adjust the rate of leakage and / or to improve the control properties A proportional valve according to any of the preceding claims, characterized in that it is formed from a material.   The exhaust connection (3) is connected to the permanently evacuated exhaust space (22) of the valve (1), which is not connected to the membrane plunger (17). Fluidly coupled to the working connection (4) via the axial hollow (12) of the membrane plate shaft (11), and the membrane plate shaft (11) is airtightly joined to the valve plunger (17) 8. Proportional valve according to any of the claims 5 to 7, characterized in that the latter is hydraulically disconnected from the operating connection (4).   The exhaust space (22) is partitioned by the first membrane (13) and the second membrane (21), wherein the membrane plate shaft (11) axially displaces the second membrane (21) by its free end. 9. A proportional valve as claimed in claim 8, characterized in that it penetrates.   The working pressure space (23) coupled with the working connection (4) of the valve (1) is partitioned by the second membrane (21) and the second sealing sheet, whereby the membrane plate (10), the valve plunger (17) And, depending on the position of the socket element (18), the operating pressure space (23) is coupled in fluid communication with the pressure air connection (5) or the exhaust connection (3) or a pressure air connection 10. Proportional valve according to claim 9, characterized in that it is disconnected from the part (5) and the exhaust connection (3).   A spring element (16, 20) for preloading the membrane plate (10) and / or the socket element (18) is also supported on the housing (15) of the valve (1). Proportional valve according to any of 10.   At least all of the membrane plates (10) are at equal distances from the central axis (M) of the membrane plate (10) and supported on the housing (15) of the valve (1) at an equal angle (α). 12. Proportional valve according to claim 11, characterized in that the membrane plate (10) is preloaded by means of three spring elements (16).   The thin film plate (10) is combined with the second thin film (21), in particular in the region of the thin film plate shaft (11), wherein the second thin film (21) is axially guided thin film plate (10) 10. Proportional valve according to claim 9, characterized in that it acts as a radial support, or directly or indirectly in another claim according to claim 9.   7. Directly or indirectly, characterized in that the valve plunger (17) is preloaded in the direction of the membrane plate shaft (11) by means of a spring (19) supported on the socket element (18). Proportional valve according to the other claims of claim 6.   6. Direct or indirect, characterized in that the valve plunger (17) in the unstressed state is separated by a given sliding distance from the socket element (18) joined to the second sealing sheet, or directly or indirectly Proportional valve according to any other claim related to claim 5.   The individual spring elements (16, 19, 20) for preloading the membrane plate (10), the valve plunger (17) and the socket element (18) are different from one another and have mutually adjusted spring characteristic curves A proportional valve according to claim 6, which is characterized by the feature of the present invention, or another claim according to claim 6 directly or indirectly.   The spring stiffness of the spring element (20) preloading the socket element (18) is higher than the spring stiffness of the spring element (19) preloading the valve plunger (17) and also preloading the valve plunger (17) 17. Proportional valve according to claim 16, characterized in that the spring stiffness of the spring element (19) is higher than that of the spring element (16) which preloads the membrane plate (10).   4. A direct or indirect control valve according to claim 3, characterized in that the valve (1) further comprises a pressure regulator (6) for adjusting the pressure present on the pressure input (33) of the pilot valve (31). Proportional valve according to claim 3 of claim 3.